LED (Light Emitting Diode) is a semiconductor luminous device. Generally, the LED chip consists of multiple compounds, such as compound of Ga (Gallium) and As (Arsenic), compound of Ga and P (Phosphorus), compound of Ga and N (Nitrogen), or compound of Ga and In (Indium). The LED chip is developed based on electroluminescence phenomenon of semiconductor PN junction. The LED chip features good photoelectric performances, such as low power consumption, small volume, long life span, high stability, fast starting and stable light wave length. Therefore, LED has been widely used in various fields, such as illumination, home appliance, display screen, indicator light, etc. Moreover, LED chip has become a preferable light source due to above features as well as advantages of no stroboflash and not easy to cause visual fatigue. With the development of the industry, LED chips with high efficiency, high-power and high-reliability are gradually in need. However, in the application side of LED chip, small-power or medium-power chips still occupy the main market. Only a few companies are involved in the manufacturing of high-power LED chips due to the problem of low yield of high-power LED chips.
Recently, more and more new types of LED chip emerge, among which high voltage LED chips and the flip chips are attracting wide interests. The high voltage LED chip is made by connecting multiple light emitting units in series, where the multiple light emitting units are made by dividing a conventional large-volume low-voltage LED chip. Current for driving the high voltage LED chip is far smaller than that for driving the large-volume low-voltage LED chip, thus the high voltage LED chip has the advantages of low package cost, high drive power source efficiency, low wire loss, etc. Further, the flip chip has the advantages of wireless welding and high performance in heat dissipation.
Currently, for high-voltage LED, interconnection of electrodes is the key factor to affect the yield of chip, and for flip chips, packaging is a key factor to affect the yield of the flip chip. For more information about high voltage LED flip chip and its manufacturing process, Chinese Patent Applications No. CN104134744A and No. CN103022334A can be referred to.